What Causes This Error When you run git pull, Git fetches the latest commits from the remote and tries to integrate them into your local branch. If both your local branch and the remote branch have commits the other doesn’t…
These are two of the original ICMP message types defined in RFC 792 (1981), alongside echo (ping) and destination-unreachable. They were designed for clock synchronization across a network, back before NTP existed. What they do The reply carries three 32-bit…
CVE-1999-0524 is an information-disclosure finding: the host responds to ICMP timestamp requests (type 13) with timestamp replies (type 14), which can leak the system clock and (historically) help an attacker with time-based attacks. The fix is simply to drop both…
Logical replication in PostgreSQL is wonderfully flexible — and wonderfully easy to misdiagnose. When something goes wrong, the symptom is almost always the same (“the subscriber is behind”), but the cause can live in any of half a dozen places:…
Large PDFs are everywhere — scanned contracts, exported reports, e-books, bank statements — and they’re almost always inconvenient. They’re slow to open, hard to email, and painful to navigate when you only need pages 47–52. Splitting a PDF into smaller…
Most Linux engineers learn SSH local port forwarding early in their careers. You have a database running on a remote server, and you want to access it from your laptop. Easy: A few seconds later, the remote PostgreSQL database magically…
Part 1 — Article: Understanding pglogical What is pglogical? pglogical is a PostgreSQL extension developed by 2ndQuadrant (now part of EDB) that provides logical replication between PostgreSQL databases. Unlike physical (streaming) replication, which copies binary WAL data block-for-block, logical replication…
pg_top is a real-time monitoring utility for PostgreSQL, similar to the Linux top command. It allows DBAs and database engineers to monitor PostgreSQL backend processes, active SQL statements, resource consumption, and database activity in real time. Installing pg_top RHEL /…
Setting a unique and descriptive identity for your server is one of the first steps in effective system administration. Without a correctly configured hostname, automated scripts and monitoring tools may fail to identify your machine, leading to confusion in logs…
In a standard Linux environment, directory permissions can sometimes be counterintuitive. By default, any user with write access to a directory has the power to delete or rename any file within that directory, regardless of who owns the file or…
